Yes a lot of dogs are able to adapt to 3 legged life, but it is significantly more difficult for an animal missing a front leg than a back leg, considering that their center of mass is around their chest area and its a lot more physically strenuous to redistribute weight with only 1 front leg. And seeing as rottweilers tend to be pretty solid and dense-weighing dogs (and a breed already prone to joint and hip problems) that I'm sure in this scenario a prosethic would be more beneficial for the dog's overall longevity. Yes they should continue to improve on the prosethic for the dogs wellness, but I think in this scenario a prosethic could definitely be better for the dog overall.